Study On The Preparation,structure And Properties Of Modified Silk Via Iron(?)-Mediated ATRP

In this thesis,surface modification of silk fabric via a novel,environmentally benign iron-mediated atom transfer radical polymerization using activators generated by electron transfer?AGET ATRP?was developed.Functional monomer 2-hydroxyethyl methacrylate?HEMA?and 2,2,3,4,4,4-hexafluorobutyl methacrylate?HFBMA?was grafted onto silk fabrics,respectively,and modified silk with good crease resistance and water repellency was prepared.The optimal grafting conditions were obtained through the investigation of structure and properties of silk fabrics before and after grafting.?1?Grafting of HEMA onto silk fabric by surface-initiated AGET ATRP was investigated,using FeCl₃ as the catalyst,ascorbic acid sodium salt?NaAsc?as the reducing agent,iminodiacetic acid?IDA?and succinic acid?SA?as the ligand.The effects of monomer concentration,pH value,temperature,reducing agent concentration,catalyst concentration and reaction time on silk modification were discussed,and the optimal grafting conditions were obtained.The results show that the reactivity of FeCl₃/IDA catalyst system was similar to FeCl₃/SA catalyst system.There appears a linear plot of grafting yield vs reaction time and monomer conversion vs reaction time,indicating the“living”/controlled process during the grafting copolymerization.?2?The effects of reaction conditions on the grafting yield of a fluorine-containing monomer HFBMA onto silk fabric with FeCl₃/IDA,FeCl₃/SA and FeCl₃/N,N,N',N'',N''-pentamethyldiethylenetriamine?PMDETA?catalyst system were discussed,and the optimal grafting conditions were obtained.The reactivity of FeCl₃/IDA catalyst system was almost the same with FeCl₃/SA catalyst system,however,a relatively low activity of FeCl₃/PMDETA catalyst system was observed.The features of“living”/controlled grafting copolymerzation using three catalyst system were also confirmed.?3?The modified silk was characterized by FTIR,Raman spectroscopy,XRD,XPS,and SEM.The results verify that the monomer was covalently grafted on the silk surface by AGET ATRP.An increased thermal ability was observed and the physical properties,like breaking strength,whiteness and air permeability decreased somewhat.?4?The crease resistance of HEMA-grafted silk was significantly improved,and the wet crease recovery angle increased higher.The contact angles of HFBMA-grafted silk surface demonstrated the better water repellency with an increase of grafting yield,which could be explained by the declining surface free energy on the fluoroalkyl-induced silk.